If you intend to race your scooter on different tracks, get both the 50 and 55 tooth procket package. This way, you can change sprocket depending on the track you are going to race on. The 50 tooth will give you more top speed if the track has a long straight and the 55 will give you more pickup if the track has many tight turns.Installation difficulty 6. The reason this part is difficult to install is that in most cases, the chain needs to be extended with 4 or 5 additional links.